At the sizes we’re talking about, it’s not filtering that is the most effective form of keeping out/in particles. What happens instead is that the particles don’t move in a straight line but have a more random motion, and if the particle in that motion happens to hit a mask fiber, it will almost certainly attach itself to it.
In fact, smaller/lighter particles are even more likely to be blocked by masks because their movmeembt is more random and they are more likely to lodge themselves into mask fibers they may hit.
Surgical and N95 masks make this even more likely because their fibers are electrostatically charged. Cloth masks try and make up for the lack of electrostatic charge with more layers and a better fit.
That’s why if you’re unable to wear an N95 or equivalent mask, the next best recommendation was double masking with a cloth mask and surgical mask, where the surgical mask provided the electrostatic charge, while the cloth mask placed over the surgical mask improved the fit.